CN115321510A - Preparation method of lithium difluorophosphate - Google Patents
Preparation method of lithium difluorophosphate Download PDFInfo
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- CN115321510A CN115321510A CN202211048401.5A CN202211048401A CN115321510A CN 115321510 A CN115321510 A CN 115321510A CN 202211048401 A CN202211048401 A CN 202211048401A CN 115321510 A CN115321510 A CN 115321510A
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/26—Phosphates
- C01B25/455—Phosphates containing halogen
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The invention belongs to the technical field of battery raw material preparation, and particularly relates to a preparation method of lithium difluorophosphate. The preparation method comprises the following steps: mixing lithium hexafluorophosphate, methyl siloxane substances and an ester organic solvent, reacting, carrying out solid-liquid separation, mixing the solid and the solvent, and filtering to obtain the lithium difluorophosphate; the temperature of the reaction does not exceed 70 ℃. Lithium hexafluorophosphate and methyl siloxane substances are used as raw materials and react in a specific ester organic solvent at the reaction temperature of not more than 70 ℃ to obtain the lithium difluorophosphate, and the solvent and byproducts in the reaction process can be fully recycled. The preparation method of the invention does not need to use hydrogen fluoride and phosphorus pentafluoride, and has mild reaction conditions and low production cost. And the prepared lithium difluorophosphate has high purity and considerable yield, and is very favorable for the application of lithium ion batteries in the field of new energy.
Description
Technical Field
The invention belongs to the technical field of battery raw material preparation, and particularly relates to a preparation method of lithium difluorophosphate.
Background
Lithium difluorophosphate has wide application in lithium ion batteries. For example, the lithium difluorophosphate is used for preparing the lithium ion battery, so that the cycle stability and the low temperature resistance of the lithium ion battery can be improved, and the internal resistance of the battery can be reduced.
With the increase of the specific gravity of lithium ion batteries in the field of new energy and the rapid development of lithium ion power batteries in the field of new energy automobiles, the demand of lithium difluorophosphate in industry is rapidly increased.
In the prior art, hydrogen fluoride is usually used for industrially producing lithium difluorophosphate, and the hydrogen fluoride has extremely strong acidity and high risk, has high requirement on anticorrosion equipment and has high risk on workers. Phosphorus pentafluoride and lithium fluoride react to produce lithium difluorophosphate in industrial production, but phosphorus pentafluoride is gas and is inconvenient to purchase directly, a phosphorus pentafluoride production workshop is often required to be built, phosphorus pentafluoride is prepared by reacting phosphorus pentafluoride and hydrogen fluoride, and hydrogen fluoride has extremely strong acidity, high risk, high requirement on anticorrosion equipment, high risk to workers and increased production cost. The industrial utilization of phosphorus pentafluoride and lithium phosphate to prepare lithium difluorophosphate often requires reaction high temperatures approaching 200 ℃, which also greatly increases production costs. The cost is high, and the application of the lithium ion battery in the field of new energy is not facilitated. In other industrial production methods, lithium difluorophosphate is prepared by taking difluorophosphoric acid as an intermediate raw material, the preparation process is complex, and the industrial production cost is high.
Therefore, it is highly desirable to provide a novel industrial method for producing lithium difluorophosphate, which does not require the use of hydrogen fluoride and phosphorus pentafluoride, and which is mild in reaction conditions and low in production cost.
Disclosure of Invention
The present invention is directed to solving at least one of the problems of the prior art described above. Therefore, the invention provides a preparation method of lithium difluorophosphate, which does not need to use hydrogen fluoride and phosphorus pentafluoride, has mild reaction conditions and low production cost. And the prepared lithium difluorophosphate has high purity and considerable yield, and is beneficial to the application of lithium ion batteries in the field of new energy.
The invention conception of the invention is as follows: lithium hexafluorophosphate and methyl siloxane substances are used as raw materials and react in a specific ester organic solvent at the reaction temperature of not more than 70 ℃ to obtain the lithium difluorophosphate, and the solvent and byproducts in the reaction process can be fully recycled. The preparation method of the invention does not need to use hydrogen fluoride and phosphorus pentafluoride, and has mild reaction conditions and low production cost. And the prepared lithium difluorophosphate has high purity and considerable yield, and is very favorable for the application of lithium ion batteries in the field of new energy.
The invention provides a preparation method of lithium difluorophosphate.
Specifically, the preparation method of lithium difluorophosphate comprises the following steps:
mixing lithium hexafluorophosphate, methyl siloxane substances and an ester organic solvent, reacting, carrying out solid-liquid separation, mixing the solid with the solvent, and filtering to obtain the lithium difluorophosphate; the temperature of the reaction does not exceed 70 ℃.
Preferably, the methylsiloxane-based substance is hexamethyldisiloxane and/or octamethyltetrasiloxane.
Preferably, the ester organic solvent is dimethyl carbonate and/or diethyl carbonate.
Preferably, the reaction temperature is 45-70 ℃, and the reaction time is 4-6 hours; further preferably, the reaction temperature is 50-70 ℃ and the reaction time is 5-6 hours.
Preferably, the reaction is carried out under the protection of an inert gas, preferably nitrogen.
Preferably, the molar ratio of the lithium hexafluorophosphate to the methylsiloxane to the ester organic solvent is 1: (2-3): (3-5); more preferably, the molar ratio of the lithium hexafluorophosphate to the methylsiloxane and the ester organic solvent is 1:2.4:4.21.
preferably, a gaseous byproduct is generated in the reaction process, and the gaseous byproduct passes through an alkaline solution to obtain methylsiloxane substances and fluorine salts.
Preferably, the gas byproduct is trimethyl fluorosilane, and the trimethyl fluorosilane is introduced into potassium hydroxide solution and distilled to obtain a liquid phase and a solid residue, wherein the solid residue is KF. The liquid phase is a mixture of hexamethyldisiloxane and water, the liquid phase is stood for layering, the upper layer is hexamethyldisiloxane, and the lower layer is water. The hexamethyldisiloxane can be recycled.
Preferably, in the solid-liquid separation process, the lithium difluorophosphate is a solid phase (white solid) which is not mixed with a liquid phase, and the liquid phase is an ester organic solvent. And distilling the liquid phase, and recovering to obtain the ester organic solvent which can be recycled.
Preferably, the solid is taken to be mixed with the solvent, and the specific process of filtering is as follows: and mixing the solid phase with ethyl acetate, filtering, distilling and drying to obtain the high-purity target product lithium difluorophosphate. And mixing the solid phase with ethyl acetate, wherein impurities can be dissolved in the ethyl acetate, lithium difluorophosphate can not be dissolved in the ethyl acetate, and drying the solid obtained by filtering to obtain the high-purity lithium difluorophosphate. The resulting liquid was filtered and distilled to obtain ethyl acetate. Therefore, the ethyl acetate can be recycled.
Preferably, the mass fraction of the potassium difluorophosphate is more than 99%, for example 99.50-99.98%.
Preferably, the yield of the lithium difluorophosphate is 50-85%.
Compared with the prior art, the invention has the following beneficial effects:
lithium hexafluorophosphate and methyl siloxane substances are used as raw materials and react in a specific ester organic solvent at the reaction temperature of not more than 70 ℃ to obtain the lithium difluorophosphate, and the solvent and byproducts in the reaction process can be fully recycled. The preparation method disclosed by the invention does not need to use hydrogen fluoride and phosphorus pentafluoride, and is mild in reaction condition and low in production cost. And the prepared lithium difluorophosphate has high purity and considerable yield, and is very favorable for the application of lithium ion batteries in the field of new energy.
Drawings
FIG. 1 is a schematic process flow diagram of the preparation of lithium fluorophosphate in example 1.
Detailed Description
In order to make the technical solutions of the present invention more apparent to those skilled in the art, the following examples are given for illustration. It should be noted that the following examples are not intended to limit the scope of the claimed invention.
The starting materials, reagents or apparatuses used in the following examples are conventionally commercially available or can be obtained by conventionally known methods, unless otherwise specified.
Example 1: preparation of lithium difluorophosphate
A preparation method of lithium difluorophosphate comprises the following steps:
mixing lithium hexafluorophosphate, hexamethyldisiloxane and dimethyl carbonate (the molar ratio of lithium hexafluorophosphate, hexamethyldisiloxane and dimethyl carbonate is 1; and distilling the filtered liquid to obtain ethyl acetate which can be recycled.
And (2) generating a gas byproduct in the reaction process, wherein the gas byproduct is trimethyl fluorosilane, introducing the trimethyl fluorosilane into 0.5mol/L potassium hydroxide solution, distilling to obtain a liquid phase and solid residues, wherein the solid residues are KF, the liquid phase is a mixture of hexamethyldisiloxane and water, the liquid phase is kept stand for layering, the upper layer is hexamethyldisiloxane, the lower layer is water, and the hexamethyldisiloxane can be recycled.
FIG. 1 is a schematic process flow diagram of the preparation of lithium fluorophosphate in example 1.
The mass fraction of the potassium difluorophosphate prepared by the preparation method is 99.97%.
When the input amount of lithium hexafluorophosphate in the above production method is 1mol, the target product lithium difluorophosphate is obtained in 0.821mol, and the yield of lithium difluorophosphate is 0.821/1 × 100% =82.1%.
Example 2: preparation of lithium difluorophosphate
A preparation method of lithium difluorophosphate comprises the following steps:
mixing lithium hexafluorophosphate, hexamethyldisiloxane and dimethyl carbonate (the molar ratio of lithium hexafluorophosphate, hexamethyldisiloxane and dimethyl carbonate is 1; and distilling the filtered liquid to obtain ethyl acetate which can be recycled.
And (2) generating a gas byproduct in the reaction process, wherein the gas byproduct is trimethyl fluorosilane, introducing the trimethyl fluorosilane into 0.5mol/L potassium hydroxide solution, distilling to obtain a liquid phase and solid residues, wherein the solid residues are KF, the liquid phase is a mixture of hexamethyldisiloxane and water, the liquid phase is kept stand for layering, the upper layer is hexamethyldisiloxane, the lower layer is water, and the hexamethyldisiloxane can be recycled.
The mass fraction of the potassium difluorophosphate prepared by the preparation method is 99.95%.
Example 3: preparation of lithium difluorophosphate
A preparation method of lithium difluorophosphate comprises the following steps:
mixing lithium hexafluorophosphate, hexamethyldisiloxane and dimethyl carbonate (the molar ratio of lithium hexafluorophosphate, hexamethyldisiloxane and dimethyl carbonate is 1; and distilling the filtered liquid to obtain ethyl acetate which can be recycled.
And (2) generating a gas byproduct in the reaction process, wherein the gas byproduct is trimethyl fluorosilane, introducing the trimethyl fluorosilane into 0.5mol/L potassium hydroxide solution, distilling to obtain a liquid phase and solid residues, wherein the solid residues are KF, the liquid phase is a mixture of hexamethyldisiloxane and water, the liquid phase is kept stand for layering, the upper layer is hexamethyldisiloxane, the lower layer is water, and the hexamethyldisiloxane can be recycled.
The mass fraction of the potassium difluorophosphate prepared by the preparation method is 99.98%.
Claims (10)
1. A preparation method of lithium difluorophosphate is characterized by comprising the following steps:
mixing lithium hexafluorophosphate, methyl siloxane substances and an ester organic solvent, reacting, carrying out solid-liquid separation, mixing the solid and the solvent, and filtering to obtain the lithium difluorophosphate; the temperature of the reaction does not exceed 70 ℃.
2. The method according to claim 1, wherein the methylsiloxane-based substance is hexamethyldisiloxane and/or octamethyltetrasiloxane.
3. The method according to claim 1, wherein the ester-based organic solvent is dimethyl carbonate and/or diethyl carbonate.
4. The method according to claim 1, wherein the reaction temperature is 45 to 70 ℃ and the reaction time is 4 to 6 hours.
5. The method of claim 1, wherein the reaction is carried out under an inert gas atmosphere.
6. The method according to claim 1, wherein the molar ratio of the lithium hexafluorophosphate to the methylsiloxane-based substance to the ester-based organic solvent is 1: (2-3): (3-5).
7. The method according to claim 1, wherein a gaseous by-product is generated during the reaction, and the gaseous by-product is passed through the alkaline solution to obtain methylsiloxane substances and fluorine salt.
8. The method according to claim 7, wherein the gas by-product is trimethylfluorosilane, the trimethylfluorosilane is introduced into a potassium hydroxide solution, and the mixture is distilled to obtain a liquid phase and a solid residue, the solid residue is KF, the liquid phase is a mixture of hexamethyldisiloxane and water, the liquid phase is allowed to stand for demixing, the upper layer is hexamethyldisiloxane, and the lower layer is water.
9. The preparation method according to claim 1, wherein in the solid-liquid separation process, lithium difluorophosphate is a solid phase which is not mixed with a liquid phase, the liquid phase is an ester organic solvent, and the ester organic solvent is obtained by distilling and recovering the liquid phase.
10. The preparation process according to any one of claims 1 to 7, wherein the mass fraction of potassium difluorophosphate is more than 99%.
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105731412A (en) * | 2015-12-29 | 2016-07-06 | 中国科学院宁波材料技术与工程研究所 | Preparation method of difluorophosphate |
| WO2018066896A2 (en) * | 2016-10-06 | 2018-04-12 | 임광민 | Method for preparing lithium difluorophosphate |
| JP2019147702A (en) * | 2018-02-26 | 2019-09-05 | 三井化学株式会社 | Method of producing lithium difluorophosphate |
| JP2019172475A (en) * | 2018-03-26 | 2019-10-10 | 三井化学株式会社 | Method for producing lithium difluorophosphate |
| CN111224164A (en) * | 2019-12-13 | 2020-06-02 | 九江天赐高新材料有限公司 | Preparation method of lithium difluorophosphate |
| CN112456465A (en) * | 2020-12-11 | 2021-03-09 | 安阳工学院 | Preparation method of lithium difluorophosphate |
| CN114634170A (en) * | 2020-12-15 | 2022-06-17 | 江苏国泰超威新材料有限公司 | Preparation method of lithium difluorophosphate |
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Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105731412A (en) * | 2015-12-29 | 2016-07-06 | 中国科学院宁波材料技术与工程研究所 | Preparation method of difluorophosphate |
| WO2018066896A2 (en) * | 2016-10-06 | 2018-04-12 | 임광민 | Method for preparing lithium difluorophosphate |
| JP2019147702A (en) * | 2018-02-26 | 2019-09-05 | 三井化学株式会社 | Method of producing lithium difluorophosphate |
| JP2019172475A (en) * | 2018-03-26 | 2019-10-10 | 三井化学株式会社 | Method for producing lithium difluorophosphate |
| CN111224164A (en) * | 2019-12-13 | 2020-06-02 | 九江天赐高新材料有限公司 | Preparation method of lithium difluorophosphate |
| CN112456465A (en) * | 2020-12-11 | 2021-03-09 | 安阳工学院 | Preparation method of lithium difluorophosphate |
| CN114634170A (en) * | 2020-12-15 | 2022-06-17 | 江苏国泰超威新材料有限公司 | Preparation method of lithium difluorophosphate |
Non-Patent Citations (2)
| Title |
|---|
| 张勇耀;陈明炎;吴海锋;赵卫娟;项文勤;沈方烈;: "二氟磷酸锂制备研究进展", 浙江化工, no. 09 * |
| 李亚楠;施翠莲;孙丹丹;曹恒喜;薛峰峰;王建萍;: "二氟磷酸锂的制备方法及其研究进展", 河南化工, no. 08 * |
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